High information capacity data carriers such as barcodes and data matrices (2D barcodes) have been widely utilised to encode key information about items and present it in a format that is machine readable and easily accessible to third parties. Information such as part numbers, date codes, manufacturer information and serial numbers can be encoded and read back through defined standards. The need to make the information held by the data carrier publicly available coupled with the desirability of conforming the data carrier to widely available international standards means that it is relatively simple to read, extract and copy. As such, the presence, use or reading of a basic data carrier cannot enable the authenticity of the carrier or associated item to be determined.
Existing authentication methods for security purposes are primarily concerned with the use of a single authentication technology, such as a particular tag. Such methods are at risk of having a limited lifetime until their security is compromised, at which point a new solution has to be incorporated, with the attendant problems of handling items already distributed with the existing compromised security feature. Similarly, it is often important to verify that the data in a data carrier on, or associated, with an item has not been compromised in addition to, or as part of, authenticating the item itself.
An object of the present invention is to simultaneously address the problems of security technology limited lifetime and authentication of data carriers.